1. Field of the Invention
The present invention proceeds from a hydraulic safety and regulating system for the steam feed of a turbine in accordance with the first part of claim 1.
2. Discussion of Background
Hydraulic safety and regulating systems are known for the steam feed of a turbine, in which a safety oil circuit is provided. Power oil, which ensures actuation of the drives of rapid-action and steam-regulating valves, is fed in a separate pipeline. The safety oil circuit ensures that in the case of a system failure the turbine can be brought into a safe operating condition. Only as much oil as covers leakage losses in each case is replenished under pressure in the safety oil circuit. The oil escaping through leaks, and the power oil leaving the drives are collected in a return line and led into an oil draining device. A pump pressurizes the oil and conveys it once again out of the oil draining device into the circulation. The pressure in the system is monitored by a safety downward-control unit. This safety and regulating system requires three pipelines, to be precise that for the power oil, that for the safety oil circuit, and the return line into the oil draining device.
This three-pipe safety and regulating system operates reliably. The outlay for building three pipelines is, however, comparatively high and in addition the danger of leaks also increases with an increasing number of pipe connections.